Instead, he got a tenant whose apartment seems like a revolving door of visitors, day and night. 

You must know all the rules and don't get upset when sometimes you mistake and pay few $$ because you forgot about expiration of 0% Right now, business credit cards give me 0% till March 2020 and with only 1.99% fees upfront while personal cards only for 12 month and 3-4% upfront.This is long term game and ideally you have to have 4+ eastanlished credit lines with different use - revolving and installment, for more than 7 years - never be late - then you'll reach to 850 FICO.Plus few other tricks - but it's alittle bit personal

We have a security cam in the entryway.

When I was 10-21 my life revolved around them.

@Joe Tomko there are a number of different strategies that can be deployed to protect their assets, but as you have gathered, the laws revolving around it are very complex.

I would consider putting a cheap wifi security cam inside the front door to get notified of motion. 

[You want the revolving aspect!]

For single tenant net lease that is absolute NNN then yes an owner typically does nothing.For MTNL -multi tenant net lease then even though in many cases absolute NNN with base plus CAM you still gave to look out for CAM caps and large Capex expenses the owner would usually pay upfront and try to recover over time.For instance if you are buying a center looking at roof and parking lot are 2 big ones.

So any legality is probably going to revolve around the notion of selling an option on a property you don't own, which is going to be a problem in every jurisdiction, not just Texas.The way you resolve that is to either sell your option (assignment) or sell an option to buy your option, instead of selling an option to buy the property.Hope that's clear.

There are some key differences to look for, mostly revolving around the water bill.